1. Field of the Invention
The present invention is directed to synthetic polymeric fibers useful in the manufacture of carpet. More specifically, the present invention is directed to a nylon fiber useful in carpet manufacture which exhibits desirable sheen with reduced sparkling luster. Most specifically, the present invention is directed to a nylon fiber having a multifoliate cross-sectional configuration.
The term "fiber" as utilized herein is defined to include fibers of extreme or indefinite length (i.e. filaments) and fibers of short length (i.e. staple). The term "yarn" as used herein is defined as a continuous strand of fibers.
2. Description of the Prior Art
Carpet made from synthetic polymeric fibers such as nylon fibers has become a popular floor covering for both residential and commercial applications at least partially because of the durability, comfort and inexpensiveness of the starting material. As use of these polymeric materials has expanded in this area, various filament cross-sectional configurations have been developed to impart desirable physical and aesthetic characteristics to carpet. Multilobal fibers, such as those disclosed in U.S. Pat. No. 3,216,186, are particularly popular in carpet manufacture because of their desirable optical properties, antisoiling ability and high bulk.
Many of these prior art multilobal filaments are constructed to produce what was at that time considered to be a desirable "sparkling luster" effect via the reflection of light in discrete beams, while eliminating sheen (see, for example, column 1, line 24 of U.S. Pat. No. 3,097,461). Current consumer desire, however, has switched to carpet having a low level of sparkle and a high degree of sheen, which is a more evenly dispersed glow of light.
U.S. Pat. No. 5,108,838 discloses a low glitter multilobal filament which includes lobes whose contours are free of flat surfaces; however, the filament disclosed in this patent has many disadvantages. For example, each lobe includes narrow necked portions which are weaker than the remainder of the lobe and which therefore could break during processing. Further, spinneret production for a fiber having such intricate surface variation can be complicated and expensive. Also, the modification ratio of this filament, because of the enlarged central portion, is lower than many conventional trilobal filaments with the resulting filaments having less body than those with higher modification ratios.